But on Friday night the versatile fullback/centre/wing looks set to return to rugby for the Chiefs and, based on trial form, play a starring role.

And he has come back bigger and stronger than ever, thanks to plenty of time spent in the gym when he was unable to run, having to recover from a grade three medial ligament strain in his knee and surgery to repair a torn groin.

"I had an adductor release after the last round-robin match against the Blues so it's been seven months to be exact," Nanai-Williams said of his long rehab road.

"It's been a long journey - a very grumpy and up-and-down roller-coaster ride to where I am now so the groins are holding up very well and the physios have done well over the last couple of months to actually strengthen them up and let them heal."

So for a long time, unable to run, he hit the gym and it shows in his upper body physical development.

"It just naturally occurred. I was eating quite often and wasn't running at all so I packed on a bit of weight - about two or three kgs - which is good because if I do play around the midfield area I've got a bit of weight to carry around and hold me up," he said.

Officially Nanai-Williams didn't return to running until the Chiefs resumed pre-season training a week into January but secretly he had tried it a couple of times in December to test out the groin.

He has been used at fullback and centre in the trial matches and was particularly impressive on attack in the final trial against the Blues from fullback on Friday night in Rotorua.

"It was quite funny playing fullback again. I had to go and familiarise myself with the running lines and what not - when to turn up etc.

"I was a bit rusty against the Reds but it was good to get rid of that rust and I felt a lot more comfortable last week and my combination with James Lowe and so on.

"I actually loved it, coming in whenever and all those little things at fullback where you have a lot of time, whereas at centre you've got to think the whole time and are constantly on your toes.

"If it is fullback this week it doesn't bother me to be honest."

He is feeling fresh both physically and mentally and is just happy to be back.

"There is nothing better than being able to run out with the brothers and going out there and doing what we love - and I love playing."